Mechanism for actuating a friction clutch



Nov. 5, 1935. 4 K. MAYBACH.

MECHANISM FOR ACTUATING A FRICTION CLUTCH Filed June 20, 1935 mi N Vas

Patented Nov.' 5, 1935 MEcnANisM Foa Ac'rUA'i'lNG A muc'rroN cnn'rcn mi Maybach, Friedl-leestafel, Germany, u.

signor to Maybach-Motorenban G. m. b. Il.,

Friedrichshafen, Gc

Appueeuon June zo, loss.' seem-ne. am

In Germany 1Ciaim.

suggested to operate such clutches by pressure means, such as compressed air or vacuum, especiallyt in such cases in'which a supplemental device ior'engaging and dis-engaging the clutch was provided for the purpose of free-wheeling.

In such casesV it is usual to make use of a piston operated by pressure means. To disengage the friction clutch itis necessary for one part Athereof to be moved over a certain distance.

'I'he corresponding travel of the piston may for example be '70 mi11imetres. If the lining of -the friction clutch is worn the distance for the movable portion of the clutch increases accordingly, so that the travel of the operating piston may increase to 200 millimetres' for example. Consequently a very big and heavy pressure cylinderis necessary for the piston, especially in great motor cars having a strong motor. The piston will never nt tightly into the cylinder,fas the tightening means are always imperfect. That is why there will always be a certain loss in pressure means, which means a great disadvany tage, especially vwhen vacuum is"made use of resulting from' the suction tube of the motor cylinders; because when running idle' with the throttle being nearly closed the motor is most likely to get a wrong mixture of air and fuel.

All these disadvantages are avoided lby my invention. I provide one piston for operating the clutch and asecond piston for causing the connection'between the first piston and the member connecting to the clutch, both pistons being moved by pressure means. 'I'he mechanism constructed according Ato my invention is very compact and need not be larger than is necessary for moving the movable part of the clutch over the usual distance for declutching, without takmg .m1-,o consideration the weer of the nnmg or the clutch.

A further object of my invention is a perfect tightness between Vpiston 'and cylinder in the end position of the pistons, that is when the rst piston has caused disengagement of the clutch and when the second piston has caused connecl Jill! 9, 1932 -mvention which will be pointed' out in the foxe -lowing part of the speciiication in which I refer 5 to the drawing which represents an example embodying my invention.

The ligure is a mere diagram showing the main elements in a vertical longitudinal ksection.

The end of the motor crank shaft I is in rigid connection with-the ily-wheel l2 being provided with an inner conical circular plane 3. Clutch member 5, splined to shaft 6, at its outer circumference is shapedso as to iit into lthe coni- 15 cal part of y wheel 2 and has 'a lining 4 which bears against plane I if the clutch members are engaged. Lever 9 is iournaled at 1 and is adapted to move clutch member 5 out of engagement with member 2 against theV pressure of 20 spring 26 which tends to hold the clutch element constantly in engagement. Tension member I0 is fastened to lever 8 at 9 and its other end is connected to member II. 'This member Il has teeth I1 and is adapted to slide within 25 I9 at the cylinder head 20. This lining I9 is more 30 Y or less elastic so as to'cause perfect air-tightness between the piston I3 and the cylinder It whenever the piston is in its right-hand position, which is always the case when the clutch members V2 and 5 arel out of engagement. Con- 35 sequently the airftightness in this position is as perfect as possible and dOeS not rely 0n the rtightening of the :piston .at its circumference against the surrounding cylinder walls, as l. is

There is an opening in the cylinder head 20 into which tube 2| nts. A cock or valve 22 allows 4to connect tube 2i either with the open air or with the tube leading from the carburetor to the cylinders of the motor; this latter tube is indi- 45 cated at 23.

- Piston I3 is again provided with a `smaller piston I5 acting in a direction substantially at right angles to that of piston I3 and against the action of spring 2B. The rod of piston I5 atv its end has teeth I6 adapted to engage with the teeth i1 of member Il. Lining 25 disposed-in the cylin-l der containing piston I5 is elastic and causes perfect air-tightness of piston i5 its lower-most 55 sosmmsimurmumngnwcnregardwpxmn The operation or the mechanism is as follows:

If cock 22 is turned into the position represented in the drawing the vacuum created within tube 23 acts through tube 2l and opening 24 (in piston I3) on piston' I5 and causes this piston to move in the direction indicated by the arrow on the piston rod so `that it presses on lining 25 and at thersame'time teeth Ii. engage with teeth 'I1 of member Il. The friction at the circumference of piston Il and the resistance oered by spring 23 are only very siight, at least much lower than the friction between piston I3 and its cylinder Il, so that piston l5 is sure to be moved ilrst. Thereafter the vacuum moves piston I3 to the right (direction of arrows) until piston I3 bears) againstlining Il. Consequently clutch members 2 and 5 are brought out oi' engagement, because member II moving together withlpiston I3 causes dis-engagement by means of member I0 and lever 8. v

When cock 22 is turned to its other position so that tube 2| is connected with the open air the vacuum in cylinder Il vanishes and piston.|3 together with member I I are moved back to the left under the action ofI spring 2G and at the same time piston i5'is pushed upward again by means of spring 28 so that teeth I6 and I1 disengage.

Whenever the lining I of the clutch is more worn member II is moved further to the left. To prevent member II from being moved to the left by shocks or other circumstances there is spring 21 which tends to draw member I I into sleeve I2; but spring 21 has ofcourse to be weaker than spring 26. 'I'hus the position of member I I within sleeve I2 depends on the wear oi lining 4. 5

By my new arrangement the way for piston I3 does not vary substantially. Consequently the cylinder need not be longer than is necessary for ordinary purposes, independently of the wear of the lining of the clutch. This means that the 10 mechanism will be comparatively light.V

Of course, it is possible to use compressed air or other pressure means instead of vacuum for operating the mechanism; it has only to be adapt'- ed for this other means, as every expert knows. 15 .I do not want to be limited to the details described or'represented in the drawing as many variations will occur to those skilled in the art.

ton rod connected to said second piston, said rod having teeth adapted to co-operate with 4said 30t teeth on said loose piston rod.

. t KARL MAYBACH. 

